Identification of a new genotype of Torque Teno Mini virus

Although human torque teno viruses (TTVs) were first discovered in 1997, still many associated aspects are not clarified yet. The viruses reveal a remarkable heterogeneity and it is possible that some genotypes are more pathogenic than others. The identification of all genotypes is essential to confirm previous pathogenicity data, and an unbiased search for novel viruses is needed to identify TTVs that might be related to disease. The virus discovery technique VIDISCA-454 was used to screen serum of 55 HIV-1 positive injecting drug users, from the Amsterdam Cohort Studies, in search for novel blood-blood transmittable viruses which are undetectable via normal diagnostics or panvirus-primer PCRs. A novel torque teno mini virus (TTMV) was identified in two patients and the sequence of the full genomes were determined. The virus is significantly different from the known TTMVs ( <40% amino acid identity in ORF1), yet it contains conserved characteristics that are also present in other TTMVs. The virus is chronically present in both patients, and these patients both suffered from a pneumococcal pneumonia during follow up and had extremely low B-cells counts. We describe a novel TTMV which we tentatively named TTMV-13. Further research is needed to address the epidemiology and pathogenicity of this novel viru

A novel astrovirus-like RNA virus detected in human stool

Several novel clades of astroviruses have recently been identified in human faecal samples. Here, we describe a novel astrovirus-like RNA virus detected in human stools, which we have tentatively named bastrovirus. The genome of this novel virus consists of 6,300 nucleotides organized in three open reading frames. Several sequence divergent strains were detected sharing 67–93 per cent nucleotide identity. Bastrovirus encodes a putative structural protein that is homologous to the capsid protein found in members of the Astroviridae family (45% amino acid identity). The virus also encodes a putative non-structural protein that is genetically distant from astroviruses but shares some homology to the non-structural protein encoded by members of the Hepeviridae family (28% amino acid identity). This novel bastrovirus is present in 8.7 per cent (35/400) of faecal samples collected from 300 HIV-1-positive and 100 HIV-1-negative individuals suggesting common occurrence of the virus. However, whether the source of the virus is infected human cells or other, for example, dietary, remains to be determined

Culturing of respiratory viruses in well-differentiated pseudostratified human airway epithelium as a tool to detect unknown viruses

Currently, virus discovery is mainly based on molecular techniques. Here, we propose a method that relies on virus culturing combined with state-of-the-art sequencing techniques. The most natural ex vivo culture system was used to enable replication of respiratory viruses. Three respiratory clinical samples were tested on well-differentiated pseudostratified tracheobronchial human airway epithelial (HAE) cultures grown at an air-liquid interface, which resemble the airway epithelium. Cells were stained with convalescent serum of the patients to identify infected cells and apical washes were analyzed by VIDISCA-454, a next-generation sequencing virus discovery technique. Infected cells were observed for all three samples. Sequencing subsequently indicated that the cells were infected by either human coronavirus OC43, influenzavirus B, or influenzavirus A. The sequence reads covered a large part of the genome (52%, 82%, and 57%, respectively). We present here a new method for virus discovery that requires a virus culture on primary cells and an antibody detection. The virus in the harvest can be used to characterize the viral genome sequence and cell tropism, but also provides progeny virus to initiate experiments to fulfill the Koch's postulate

A novel genus in the order Picornavirales detected in human stool

Recently, four new viruses belonging to an unassigned family within the order Picornavirales were identified in excrements of healthy carp (fisavirus) and pigs (posavirus 1, 2 and 3). We report the detection and characterization of a fifth virus present in human faeces. The virus, named human stool-associated RNA virus (husavirus), contains a single ORF encoding a putative 2993 AA polyprotein, with a Hel-Pro-Pol replication block, typical for the Picornavirales. Phylogenetic analysis revealed that the closest relative to husavirus is posavirus 1, and together they cluster with fisavirus, posavirus 2 and 3 and a roundworm (Ascaris suum) derived virus. Husavirus was detected in eight human stool samples collected in 1984 (n = 2), 1985 (n = 4), 1995 (n = 1) and 2014 (n = 1). From three strains of husavirus from 1984 and 1985 the full genome sequence was determined, showing less than 5 % intraspecies variation in the nucleotide composition. The host of this virus remains to be determined

Influenza and other respiratory viruses involved in severe acute respiratory disease in northern Italy during the pandemic and postpandemic period (2009-2011)

Since 2009 pandemic, international health authorities recommended monitoring severe and complicated cases of respiratory disease, that is, severe acute respiratory infection (SARI) and acute respiratory distress syndrome (ARDS). We evaluated the proportion of SARI/ARDS cases and deaths due to influenza A(H1N1)pdm09 infection and the impact of other respiratory viruses during pandemic and postpandemic period (2009-2011) in northern Italy; additionally we searched for unknown viruses in those cases for which diagnosis remained negative. 206 respiratory samples were collected from SARI/ARDS cases and analyzed by real-time RT-PCR/PCR to investigate influenza viruses and other common respiratory pathogens; also, a virus discovery technique (VIDISCA-454) was applied on those samples tested negative to all pathogens. Influenza A(H1N1)pdm09 virus was detected in 58.3% of specimens, with a case fatality rate of 11.3%. The impact of other respiratory viruses was 19.4%, and the most commonly detected viruses were human rhinovirus/enterovirus and influenza A(H3N2). VIDISCA-454 enabled the identification of one previously undiagnosed measles infection. Nearly 22% of SARI/ARDS cases did not obtain a definite diagnosis. In clinical practice, great efforts should be dedicated to improving the diagnosis of severe respiratory disease; the introduction of innovative molecular technologies, as VIDISCA-454, will certainly help in reducing such "diagnostic gap.

Identification of a novel human rhinovirus C type by antibody capture VIDISCA-454

Causative agents for more than 30 percent of respiratory infections remain unidentified, suggesting that unknown respiratory pathogens might be involved. In this study, antibody capture VIDISCA-454 (virus discovery cDNA-AFLP combined with Roche 454 high-throughput sequencing) resulted in the discovery of a novel type of rhinovirus C (RV-C). The virus has an RNA genome of at least 7054 nt and carries the characteristics of rhinovirus C species. The gene encoding viral protein 1, which is used for typing, has only 81% nucleotide sequence identity with the closest known RV-C type, and, therefore, the virus represents the first member of a novel type, named RV-C5